Counterbalance for doors



, June 9,1931.

F. H. M CORMICK COUNTERBALANCE FOR DOORS 2 Sheets-Sheet 1 Filed Oct. 12;

Inventor: Francis H. Mc: Cormpc 0% His At-tbrneg, I

June 9, 1931. F. H; M CORMICK COUNTERBALANCE FOR DOORS 2 Sheets-Sheet 2 Filed Oct. 12. 1929 llll Inventor: Francis H. MCCOTTHIGK,

M His Attorneg.

Patented June 9, 1931 UNITED STATES PATENT oFFIcE FRANCIS H. MCCORMICK, OF GLEN ELLYN, ILLINOIS, ASSIGNOR TO EDISON ELMO API'LIANCE COMZPANY, OF CHICAGO, ILLINOIS, A. CORPORATION OI NEW: YORK,

COUNTERBALANCE FOB. DOORS Application filed October 12, 1929. Serial No. 399,331.

My invention relates to a counterbalance for doors and like movable inembers and has for its object the provision of an improved device of this character.

More specifically, my invention relates to an improved counterbalance for oven doors and the like. My invention is especially directed to drop oven doors that swing about a horizontal axis, and has for a further object the. provision of a counterbalance for the door arranged so that all the parts of the counterbalance are concealed and yet are readily accessible for adjustment, replacement or repair.

In accordance with my invention, I provide a strip like spring -mechanically connected with the door so that the spring will be flexed by the opening movement of the door to counterbalance its.weight. Preferably, the spring will be curved initiall so that it will have a substantially semi-elliptical form when the door is in its closed osition. In order to steady the motion 0 the door I provide auxiliary damping means. I have found that the spring together with the damping means will give the door a steady motion and will cause the door to stand at practically any position in which it has been Y placed.

The spring and likewise its mechanical door connections and the damping means are so positioned that they are concealed by the range structure. I v

For a ,more complete understandi of my invention reference should be had to the accompanying drawings in which Fig. 1 is an elevation of an electric range embodying my invention; Fig. 2' is an elevation on a larger scale of a portion of the range shown in Fi 1; Fig. 3 is a vertical section taken throug line 3-3 of Fig. 2 illustrating the doorin its closed position; Fig. 4 is a view similar to Fig. 3 but illustrating the door in its open position; Fig. 5 is an elevation of a portion of an electnc range embodying a modified form of my invention, ortions of the range is a view similar to Fig. 6 but illustrating the door in its open position.

Referring to the drawings, I have shown my invention in one form as applied to an electric range althoughobviously any form of heat may be used. As shown, in Figs. 1 an to 4 inclusive, the range is provided wit oven compartment 10 on the ri ht hand side, as viewed in Figs. 1 and 2, an with a cooking top 11 on the left hand side. Suitable electric heating elements (not shown) are provided for the oven and cooking top.

It will be understood that the oven heat ing chamber will be formed from a pair of si e walls 12 and 13, an end wall (not shown) tween which a suitable heat insulating material 17 such as rock wool is placed.

A suitable base or frame 18 of angle members formed into rectangular shape is provided for the oven and cooking top. It will v be understood that the outer metallic linings provided for the oven walls will be extended downwardly below the. bottom wall of the oven to the angular framework to Y which they will be suitably'secured as by screw fastening means (not shown). Thus,

the oven will be supported in spaced relation with respect to its supporting framework.

Suitable legs 19 are'provided to support the framework.

The door 16 is hinged to move about its lower horizontal edge so that it may be swung from a vertical closed position (Fig. 3) to a horizontal open position (Fig. 4). As shown, the hinge structure provided for the door comprises a pair of hinge brackets 20. Each hinge bracket is of bell-crank shape,

the arms 20a and 20b of the bell-crank being joined by an arc-shaped arm 200. As shown, the arms 20a serve to support the door and each is provided with a flanged portion 1 which projects at right angles to-the plane 206 and 200, and which of the arms 20a,

secured to the door by any suitable means,

such as by welding. These flanges as shown p are relatively long and relatively wide so as to provide a substantial bearing area against the door.

It will be observed that the bell-cranks are pivotally mounted at their apexes upon received by the clips. The curved portion 200 of each bell-crank is passed through a suitable slot-like aperture provided in the door frame. Each of the other arms 20b of the bell-cranks is projected beyond the curved pgrtion 200 so as to form a latch-like memr 22 which is arranged to engage an abutment or stop in 23 when the door has been moved to its ull open position. It will be observed that the arms 20a and 20b of each bell-crank form an angle slightly greater than 90 so that the stop pins, which necessarily must be displaced inwardly from the vertical position assumed by the closed door, will permit the door to be moved to a horizontal position when opened.

In order to balance the door so that it will not fall rapidl to its open position by reason of its gravity bias and moreover, in order to cause the door to stand in practically any position to which it has been moved, I provide a suitable counterbalance strip-like spring 24 suitably mechanically connected with the door and suitably supported by the framework. As shown, the spring is curved so that it normally assumes a semi-elliptical shape. The spring is supported by the front angle member 0 the framework 18 preferably so that its center portion lies directly below one of the hinge bracket members 20. In other words, the spring is positioned so that the vertical plane containing the three arms 20a, 20b and 200 of the hinge bracket will pass sub stantially through the longitudinal center of the spring. As shown, this spring is thus positioned below the left-hand hinge. This central portion of the spring is mechanically connected with the hinge bracket by means of a vertically disposed tension link 25. As shown, the upper end of this link is mechanically connected with the arm 20?) of the bellcrank by means of a pin 26 provided on the tension link and which is arranged to be received b a hook member 27 provided on the arm. he lower end of the tension link is mechanically connected with the spring by means of a clip or saddle 28. This saddle I preferably will be of substantially thesame width as the spring and will have a length so that a relatively large bearing area will be provided for the spring. The saddle is provided with upright flange-like members 29 which serve to carry a pin 30 disposed crosswise of the spring. The lower end of the tension link is curved about this pin in hook-like fashion.

The spring 24 is secured at each end to the frame by means of a suitable lost'motion connection shown as a pin and slot connection. As shown, this pin and slot connection comprises a bolt-like member 31 secured to the horizontal portion of the front flange of the framework 18, the bolt being passed through a longitudinal slot provided in the end portion of the spring. Preferably, the bolt 31 will be provided with a bushing 32 which is received directly by this slot. Also it is preferable to position a pair of washers 32a on opposite sides of the spring. It'will be understood that when the spring is flexed by the opening movement of the door, the frictional forces occurrin between each end portion of the spring an the washers positioned between the spring and the frame 18 will provide a considerable damping effect. In other words these frictional forces will serve to steady the motion of the door.

In operation, it will be understood that the door, when it is moved to its open position, will rotate the hinge brackets 20 in a counterclockwise direction, as viewed in Figs. 3 and 4, and thereby flex the spring 24. The spring, therefore, will exert a resisting or counterbalancing force to the weight of the door. It will be observed that as the leverage of the force of gravity acting on the door is increased by the openlng movement of the door, the spring will be subjected to an increasing stress which will serve to substantially balance the increased gravity force. Likewise, when the door is being closed, the spring will serve to counterbalance the weight of the door.

It will be observed that the frictional forces occurring between the end portions of the spring and the supporting structure will serve to steady the motion of the door. By reason of this tendency of the foregoing construetion to steady the motion of the door, it will stand at practically any position to "which it has been moved.

An important feature of my invention is the arrangement of the hinge and counterbalance construction in that all of the elements are concealed by the range structure. It will be observed by reference to the drawings that the spring 24 is concealed by the. depending flange of the framework 24; and the hinge bracket 20, their supporting rod 21 and also the tension link 25 are concealed by the range front plate. However, the hinge and counterbalance elements are readily accessible for replacements, repairs and adjustments. All of these elements may be removed or replaced witllgout the necessity of employing special too In the event the range be provided with a relatively heavy door, it is sometimes desirable to supply a counterbalance spring 24 for each hinge'or to supply only one spring for both hinges. In the latter arrangement the spring will be of semi-elliptical form and will be secured at its central portion to the framework in a position reversed to the position of the spring shown in Fig. 1.

Referring to Figs. 5, 6 and 7, I have shown a modified form ofvmy invention in which a spring arrangement of this character is provided. The oven. door 40 of this form, like the door of the first form, shown in Figs. 1-4, is provided with a hinge bracket 41 at each end. These brackets are similar to the brackets provided for the first form in that they have a bell-crank shape. Thus, each bracket has a flanged arm 41a and a second arm 41?) arranged substantially at right angles to the first arm and connected thereto by a third arm 410. Each flange portion 41a is secured to the door while each portion 41?) is provided with a latch-like projection 42 arranged to engage a suitable stop 43 when the door is in its open position (Fig.

7 The arm portion 410 in the assembled range passes through a suitable slot-like aperture 44 provided in the door frame.

The arm 41?), alsov serves to mechanically connect the door with its counterbalance.

This counterbalance comprises a flat striplike spring 46 which when the door is in its closed position (Figs. 5 and 6) 'has a. semiellipt-ical form. As shown, this spring is secured' at its central portion to the range, a suitable U shaped bracket 47 being provided for this purpose. One leg of this bracket is secured to the oven supporting frame 48 while the other leg is secured to the bottom outer lining of the oven. It will be understood that the spring wil be secured to the bracket by any suitable means. Thus, the spring may be either boltedor welded to the bracket. I

The spring 46 is positioned so that with the door in its closed position (Figs. 5 and 6), its end portions curve away from the bottom of the oven and as shown, each end of the spring is mechanically connected with the hinge bracket 41?) positioned at that end of the oven. As shown, each spring end is connected with its bracket byimeans of a vertically disposed link 50. This link is passed through an aperture in the end portion of the spring and is provided at its lower end with a head to prevent it from passing therethrough. The upper end of the link is bent at right angles to the body of the link and is received in an aperture provided for it in the bracket arm 416. A suitable pin 51 serves to secure the upper end of the link.

It will be observed that by reason of this construction, a single spring 46 is mechanithroughout both its opening and closing movements. Thus, when the door is opened the ends of the spring will be moved upwardly'to the position shown in Fig. 7 and when the door is closed these ends will be returned to their initial positions shown in Figs. 5 and 6. It'will be understood that the spring will be suificiently strong to counterbalance the door between the limits of its entire movement.

Suitable damping means also may beprovided in this arrangement. For this purpose I provide a strip-like member 52 positioned substantially coextensive with the spring and below the spring between it and the headed ends of the links 50. The strip-like member is provided with suitable apertures to receive the 1inks50. The member 52 performs a function similar to the angle support 18 of Fig. 1 in that it frictionally engages the end portions of the spring 46 as it is being flexed by the movement of the door. It will be understood that these frictional forces which occur'between the end portions of the spring and the strip like member 52 will serve to damp, i. e. steady the motion of the door.

The hinge brackets 41 of this arrangement instead of being fixedly pivoted to a rod extending across the oven as are the brackets of Figs. 1-4, are provided with separate fixed supports 55 upon which they are removably mounted. Each support 55 is mounted with: in a suitable casing 56. It will be understood that this casing also serves to protect the hinge and counterbalance mechanism from the rock wool insulation between the inner and outer linings of the oven.

et is provided at its lower end with a hooklike hearing member 57. This member is proportioned so that it may readily be positioned upon or removed from its support 55 but is large enough to provide a sufficient bearing area. -It will be understood that in the assembled range the spring counterbalance serves to maintain the door with its brackets secured on their hinge supports.

It will be observed that the arm 41a is mechanically connected with the arm 41?) only by means of the portion 410. In other words the arms 41a and 416 are not mechanically connected at the apex of the right angle but are separated sufliciently at this point to receive the bottom portion of the door frame. It will be understood that by reason of this construction, the door in being opened will be swung downwardly and out- 1 rue As shown, the arm 41b of each hinge brackwardly clear of the lower portion of the door the door may be readily assembled or removed. In order to assemble the door it is merely necessary to project the arms 41b through the slots 44 provided in the door frame and then lower the door slightly so 5 that the hook-like bearing members 57 will be received by their respective supporting rods 55. To remove the door it is merely necessary to disconnect the counterbalance, lift the door from its supporting members 515 and withdraw the arms 410 through the s ots.

Moreover, the foregoing bracket and counterbalance construction is of advantage in that all of the parts of the mechanism are concealed. This improves the appearance of the stove. The appearance is further improved in that it is possible by reason of this arrangement of the door supports to shape the lower portion of the door to conform with the upper portion. Thus, the lower corners of the door, as shown, are rounded as are the upper corners.

What I claim as new and desire to secure by Letters Patent of the United States, is:

l. The combination with. a member movable between a pair of limiting positions and biased to one of said positions, of a counterbalancing spring cooperating with said member and an auxiliary member frictionally engaging said spring so as to damp the motion of said first member.

' 2. The combination with a member movable between a pair of limiting positions and biased to one of said positions, a counterbalance for said member comprising a striplike spring, means mechanically connecting said spring with said member so that said spring is flexed by the movement of said member to said one position and a member 40 having portions thereof definin substantially plane surfaces arranged to ictionally engage portions of a surface of said spring as said s ring is flexed by the movement said member so as to damp the motion of said member.

3. A counterbalance for a member mounted to move between a plurality of positions and biased to move to one of said positions comprising a semi-elliptical spring, means mechanically connecting said spring with said movable member so that said spring is flexed by the movement of said member to said one position to counterbalance said bias and means for su porting said spring to provide for frictiona en agement between'portions of said spring and said support, said supporting means thereb serving to damp the motion of said member.

4. The combination with an oven or the W like rovided with walls forming a heatin cham r havinga front opening therein 0 a'door for said opening, hinge means for pivotally supporting said door at its lower edge so that said door can be moved about a hori- 66 zontal axis to its open and closed positions,

a counterbalance strip-like spring for said door, means for securing said ring beneath said door, a lever mechanica y connected with said door, a link mechanically connecting said lever with said spring so that the spring is flexed by the movement of said door to counteract its weight, and auxiliary means for damping the motion of said door.

5. The combination with an oven or the like provided with walls forming a heating chamber having a front opening therein of a door for said opening, hinge means for pivotally supporting said door so that said door ma be dropped to an open position, a counter alance strip-like spring for said door lever means for mechanically connecting said door with said strip-like spring, means for sup orting said spring so that the spring is exed by the movement of said door to counteract its weight and a strip-like member for frictionally engaging the ends of said sprin so as to damp the motion of said door.

6. he combination with .a pivotally mounted member movable between a substantially vertical position and a substantially horizontal position of a counterbalance for said member comprising a lever mechanically secured to said member, a stri -like semielliptical spring member, means or supporting said spring member at its end portions, sald means providing for relative movement between these end portions and the spring support, and a link mechanically connectin the central portion "pf said spring and said lever so that the tension of said spring together with the frictional resistance to the movement between said spring and its suppprt counterbalances the weight of said memr to maintain the member in any position between its limits of movement.

7. The combination with a normally closed oven door or the like of a plurality of hellcrank hinge members for said door, means for securing said door to corres nding arms of said bell-cranks, means or pivotally mounting said bell-cranks so that said door may be swung from a vertical closed position to a horizontal open sition and counterbalancing means for said door comprising a springlnormally semi-elliptical, means mechanica y connecting the central portion of said spring with the free arm of one of said bell-cranks and means for supporting said spring at its end portions so as to rovide for freedom of movement between sai spring and its supporting means.

8. An oven comprising walls fo a heating chamber, said heating chamber being provided with a front opening therein, supporting means for said heating chamber comp a structural framework, said framewor being provided with a depending flange, a door for said opening, hinge means pivotally mounting said door so that it may moved from .a vertical closed position to ahorizontal open position, said hinge means comprising a bell-crank to one arm of which said door is secured, means for pivotally mounting said bell-crank, a strip-like spring connected to the other arm of said bell crank so as to counterbalance the weight depending flange for frictionally engaging the end portions of said strip-like spring so as to damp the motion of said door. a

9. The combination with a stove provided with walls forming an oven chamber having a front opening therein of a plurality of horizontally disposed angle members connected to form a supporting frame for said Walls upon which the Walls are supported in spaced relation, said framework having a peripheral depending flange, hinge means pivot-ally mounting said door 1: r swinging motion from a vertical closed horizontal open position, said hinge means comprising a pair of bell-crank hinge arms,

means for securing said door to corresponding arms of said bell-cranks so that said door is secured on one side of the pivotal axis of said bell-cranks, a hook mounted on the other arm of one of said bell-cranks on the other side of said pivotal axis, a strip-like counterbalancing spring for said door, means for supporting said spring at its end portions to one of said angle members lengthwise ofthe member so that the spring is concealed by said depending flange, said end supports providing for limited relative movement between said spring and its supporting frame, and a tension link mechanically connecting said hook and the central portion of said spring, said spring being initially curved so as to'assume a substantially semi-elliptical form with the door in its vertically closed position. 10. The combination with a' pivotall mounted member biased to move in one direction of a counterbalance for said member comprising a'spring member and means for mechanically connecting said spring member with said pivotally mounted member at a plurality of points so that said spring exerts V a force in a direction to counterbalance said ing a front opening therein of a door for said bias and an auxiliary member frictionally engaging said spring so as to damp the motion of said first member. 7 I

' 11. The combination with an oven provided with walls forming a heating chamber havopening, a pair of hinge brackets for pivotally supporting said door so that said door can be swung about a horizontal axis to its open and closed positions, a counterbalance strip-like spring for said door, means for'securing said spring at its central portion b eneath said pivotal axis so that the ends of said osition to a spring are substantially in vertical alignment with said hinge brackets respectively, linkvided with walls forming a heating chamber having a front opening therein of a door for said opening, a pair of hinge brackets pivotally supporting said door so that it may be dropped to an open position, a counterbalance strip-like spring for said door, means for securing said spring at its central portion so that each end of said spring is positioned beneath one of said hinge brackets and so that said spring assumes a semi-elliptical form with the door in its closed position, link members for connecting the ends of said spring with said hinge brackets, and means for damping the motion of said door comprising a strip-like member positioned below said spring and secured so that it will frictionally engage the end portions of said spring.

13. The combination with an oven or the like having walls forming an oven chamber with a front opening therein of a door for said opening, means for pivotally supporting said door for movement about a horizontal axis cally connecting said spring member with said brackets so that said spring member operates to hold said brackets on their respective fixed supports, and to counterbalance the Wei ght of said door, and auxiliary means comprising a strip-like member for frictionally engaging portions of said spring member so as to damp the motion of said ,door.

14. The combination with an oven or the like provided with walls forming-a heating chamber having a front opening therein of a door. for said opening, a pair of hinge brackets for pivotally supportingsaid door at its end ortions so that said door can be swung a out a fixed horizontal axis to its open and closed positions, a strip-like spring for said door, means for securing said spring at its central portion beneath said pivotal axis so that'the longitudinal axis of said spring is substantially parallel withsaid pivotal axis, said spring being substantially coextensive with said door so that its ends are with said in substantial vertical alinment v be y mem rs hinge brackets respective hnk connecting the ends of said sprin with said brackets respectively so that sai spring is flexed b the movements of said door to its open an closed ositions to thereby counterbalance the weig t of said door, and a member frictional? en aging ortions of the area of a surface 0 sai stripike spring so as to damp the motion of said door.

In witness whereof, I have hereto set my hand this seventh day of October, 1929.

FRANCIS H. MGCORMICK. 

